Subject: grow: Re: Last Call: 'IP Version 6 Addressing Architecture' to Draft Standard

From: Joe Abley <[email-masked]>
Date: Wed, 6 Apr 2005 13:06:22 -0400

Hi,

I would like to propose that the restriction on the use of anycast for 
host-based services be lifted in conjunction with the revision to the 
v6 addressing specification. Specifically, that the following text in 
section 2.6 be removed:

>    There is little experience with widespread, arbitrary use of 
> Internet
>    anycast addresses, and some known complications and hazards when
>    using them in their full generality [ANYCST].  Until more experience
>    has been gained and solutions are specified, the following
>    restrictions are imposed on IPv6 anycast addresses:
>
>       o An anycast address must not be used as the source address of an
>         IPv6 packet.
>
>       o An anycast address must not be assigned to an IPv6 host, that
>         is, it may be assigned to an IPv6 router only.

An alternative approach (updating the addressing spec using a separate 
document) can be found in draft-jabley-v6-anycast-clarify-00. To 
paraphrase that draft, there is increasing production experience with 
the use of anycast to distribute services with both IPv4 and IPv6, and 
I believe we have reached a suitable point in our experience with 
anycast that the restrictions quoted above can be lifted.

There is community support for this position, most recently expressed 
at the grow meeting Minneapolis (and in subsequent messages to the grow 
list). I have also received  private mail in support of this proposal; 
I have not yet heard anybody speak in support of retaining the text 
above. Brian Haberman tells me he will shortly raise the question on 
the ipv6 list, to gauge opinion there.

[There are many caveats for the deployment of anycast services, and the 
technique is certainly not universally applicable to all routing 
systems and all services. A treatment of the applicability and 
potential pitfalls in anycast deployment (for both v4 and v6) is in 
progress in draft-ietf-grow-anycast-00. This draft is at least another 
rev away from wglc, but such a rev could probably be made to happen 
fairly quickly if the v6 anycast position was to be clarified (e.g. in 
the interests of providing a stable normative reference for 
draft-ietf-ipv6-addr-arch-v4).]

Regards,

Joe

On 6 Apr 2005, at 11:05, The IESG wrote:

> The IESG has received a request from the IP Version 6 Working Group WG 
> to
> consider the following document:
>
> - 'IP Version 6 Addressing Architecture'
>    <draft-ietf-ipv6-addr-arch-v4-02.txt> as a Draft Standard
>
> The IESG plans to make a decision in the next few weeks, and solicits
> final comments on this action.  Please send any comments to the
> [email-masked] or [email-masked] mailing lists by 2005-04-20.
>
> The file can be obtained via
> http://www.ietf.org/internet-drafts/draft-ietf-ipv6-addr-arch-v4-02.txt
>
> Implementation Report can be accessed at
> http://www.ietf.org/IESG/implementation.html
>
>
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> [email-masked]
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